This project addresses the potential interaction between a select foodborne mycotoxin and malignant hyperthermia in pigs. Malignant hyperthermia is an inherited disorder that results in excessive rates of skeletal muscle metabolism when these individuals are exposed to certain stimuli. The genetic defect, now characterized in both pigs and humans, resides in the gene which encodes the skeletal muscle calcium channel protein. Specifically, the defective channel protein is unable to tightly control the release of calcium from the sarcoplasmic reticulum under certain conditions, and subsequently leads to excessive cytoplasmic levels of calcium. The mycotoxin cyclopiazonic acid is produced by various molds found in/on foodstuffs consumed by animals and humans. Cyclopiazonic acid specifically inhibits the skeletal muscle calcium ATP-ase, the protein responsible for pumping cytoplasmic calcium into the sarcoplasmic reticulum. By inhibiting the reuptake of calcium, ingested cyclopiazonic acid may contribute to episodes of malignant hyperthermia in affected individuals. Cyclopiazonic acid for these studies was purified from cultures of penicillium greseofulvum. The structure and purity of original extracts were confirmed by mass spectroscopy.